I'm not an expert in either language but have you also given F# a though? The compiler is open source and should run under Mono. I do know it's heavily influenced by OCaml.
I really need Linux to be the first class citizen (yes I see MS has bought Xamarin but still). Also last I looked, F# wasn't looking any better than Ocaml on multinode distributed computing (please do correct me if I'm wrong).
Xamarin is a C# shop, mono as a platform for F# is independent of this, and if I'm not mistaken the F# compiler is open source[0] under the Apache 2.0 License. There are a few shops who have praised F# for it's multicore capabilities[1], but again I am not a full expert so it may require independent research. MonoDevelop supports F# as well. There are Linux build instructions in the GitHub repository.